Inrush current is an instantaneous input current drawing by an electrical device, such as a DC-DC converter, when first turn on. Inrush limiting circuits are electrically coupled to the DC-DC converter and are used to manage power quality along shared power lines and to sustain electromagnetic interference (EMI) requirements for operation of DC-DC converters within complex electronic systems. For example, DC-DC converters typically share an input power line with other circuits that may be susceptible to damage due to spikes in voltage and/or current along the input power line. Additionally, the input circuits for the DC-DC converter may degrade if over stressed with current and/or voltage spikes output by conventional inrush limiting circuits. Conventional inrush limiting circuits typically prevent excess agitation on input power delivery ports that may damage other circuits being serviced by the same input power line. Further, conventional inrush limiting circuits typically prevent excessive current surges from stressing input EMI filter components when the DC-DC converter is powered.
However, conventional inrush limiting circuits use either a passive approach using an inductor or bypass-resistor/switch approach, or an active controlled current approach to stabilize the power line. The conventional inrush limiting circuits generally include large relays and are generally heavier and bulkier due to the large components. Further, conventional inrush limiting circuits exhibit long startup delay times that may not be acceptable for subsequent circuitry of a DC-DC converter. Additionally, DC-DC converters often require additional and separate circuitry for input voltage surges to accommodate output surges of the conventional inrush limiting circuits. Conventional systems typically require large transient voltage suppressors that add significant cost and weight to the systems.